A sail is a tensile structure—made from fabric or other membrane materials—that uses wind power to propel sailing craft, including sailing ships, windsurfers, ice boats, sail-powered land vehicles. Sails may be made from a combination of woven materials—including canvas or polyester cloth, laminated membranes or bonded filaments—usually in a three- or four-sided shape. A sail provides propulsive force via a combination of lift and drag, depending on its angle of attack—its angle with respect to the apparent wind. Apparent wind is the air velocity experienced on the moving craft and is the combined effect of the true wind velocity with the velocity of the sailing craft. Angle of attack is constrained by the sailing craft's orientation to the wind or point of sail. On points of sail where it is possible to align the leading edge of the sail with the apparent wind, the sail may act as an airfoil, generating propulsive force as air passes along its surface—just as an airplane wing generates lift—which predominates over aerodynamic drag retarding forward motion.
The more that the angle of attack diverges from the apparent wind as a sailing craft turns downwind, the more drag increases and lift decreases as propulsive forces, until a sail going downwind is predominated by drag forces. Sails are unable to generate propulsive force if they are aligned too to the wind. Sails may be attached to a mast, boom or other spar or may be attached to a wire, suspended by a mast, they are raised by a line, called a halyard, their angle with respect to the wind is controlled by a line, called a sheet. In use, they may be designed to be curved in both directions along their surface as a result of their curved edges. Battens may be used to extend the trailing edge of a sail beyond the line of its attachment points. Other non-rotating airfoils that power sailing craft include wingsails, which are rigid wing-like structures, kites that power kite-rigged vessels, but do not employ a mast to support the airfoil and are beyond the scope of this article. Sailing craft employ two types of the square rig and the fore-and-aft rig.
The square rig carries the primary driving sails are carried on horizontal spars, which are perpendicular or square, to the keel of the vessel and to the masts. These spars are called yards and their tips, beyond the last stay, are called the yardarms. A ship so rigged is called a square-rigger; the square rig is aerodynamically most efficient. A fore-and-aft rig consists of sails that are set along the line of the keel rather than perpendicular to it. Vessels so rigged. Archaeological studies of the Cucuteni-Trypillian culture ceramics show use of sailing boats from the sixth millennium BCE onwards. Excavations of the Ubaid period in Mesopotamia provides direct evidence of sailing boats. Sails from ancient Egypt are depicted around 3200 BCE, where reed boats sailed upstream against the River Nile's current. Ancient Sumerians used square rigged sailing boats at about the same time, it is believed they established sea trading routes as far away as the Indus valley; the proto-Austronesian words for sail and other rigging parts date to about 3000 BCE when this group began their Pacific expansion.
Greeks and Phoenicians began trading by ship by around 1200 BCE. Triangular fore-and-aft rigs were invented in the Mediterranean as single-yarded lateen sails and independently in the Pacific as the more efficient bi-sparred crab claw sail, continue to be used throughout the world. During the 16th-19th centuries other fore-and-aft sails were developed in Europe, such as the spritsail, gaff rig, genoa and Bermuda rig mainsail, improving the upwind sailing ability of European vessels; the fore-and-aft rig began as a convention of southern Europe and the Mediterranean Sea: the gentle climate made its use practical, in Italy a few centuries before the Renaissance it began to replace the square rig which had dominated all of Europe since the dawn of sea travel. Northern Europeans were resistant to adopting the fore-and-aft rig, despite having seen its use in the course of trade and during the Crusades; the Renaissance changed this: beginning in 1475, their use increased and within a hundred years the fore-and-aft rig was in common use on rivers and in estuaries in Britain, northern France, the Low Countries, though the square rig remained standard for the harsher conditions of the open North Sea as well as for trans-Atlantic sailing.
The lateen sail proved to have better upwind performance for smaller vessels. Aerodynamic forces on sails depend on wind speed and direction and the speed and direction of the craft; the direction that the craft is traveling with respect to the true wind is called the "point of sail". The speed of the craft at a given point of sail contributes to the apparent wind —the wind speed and direction as measured on the moving craft; the apparent wind on the sail creates a total aerodynamic force, which may be resolved into drag—the force component in the direction of the apparent wind—and lift—the force component normal to the apparent wind. Depending on the alignment of the sail with the apparent wind, lift or drag may be the predominant propulsive component. Total aerodynamic force resolves into a forward, driving force—resisted by the medium through or over which the craft is passing —and a lateral force, resisted by the underwater foils, ice runners, or wheels of the sailing craft. For apparent wind angles aligned with the entry point of the sail, the sail acts as an airfoil and lift is the predominant component of propulsion.
A grommet is a ring or edge strip inserted into a hole through thin material a sheet of textile fabric, sheet metal or composite of carbon fiber, wood or honeycomb. Grommets are flared or collared on each side to keep them in place, are made of metal, plastic, or rubber, they may be used to prevent tearing or abrasion of the pierced material or protection from abrasion of the insulation on the wire, line being routed through the penetration, to cover sharp edges of the piercing, or all of the above. A small grommet may be called an eyelet, used for example on shoes and sails for lacing purposes. In electrical applications these are referred to as "insulating bushings". Most common are molded rubber that are inserted into small hole diameters up to 2" in diameter. There are many hole configurations from standard round to assorted U-shapes. Larger penetrations that are irregular in shape as well as long straight edges use extruded or stamped strips of continuous length; these continuous length materials are referred to as "grommet edging".
These are quite common in applications that range from telecom switches and data center cabinets to complex and dense wire/cable and hydraulic tubing in aircraft, transportation vehicles and medical equipment. Grommets are used to reinforce holes in leather, shoes and other fabrics, they can be made of metal, rubber, or plastic, are used in common projects, requiring only the grommet itself and a means of setting it with a punch, a metal rod with a convex tip. A simple punch sold with the grommets, can be struck with a hammer to set the grommet, it can be set with an electronic, pneumatic, or gas-powered machine. There are dedicated grommet presses with punch and anvil, as shown in the picture, ranging from inexpensive to better-quality tools, which are somewhat faster to use, they are used to strengthen holes. The grommet prevents the cord from tearing through the hole, thereby providing structural integrity. Small grommets are called eyelets when used in clothing or crafting. Eyelets may be used purely decoratively for crafting.
When used in sailing and various other applications, they are called cringles. Sometimes field workers refer to them as grunyons. If metal or another hard material has a hole made in it, the hole will have sharp edges. Electrical wires, rope, lacings, or other soft vulnerable material passing through the hole can become abraded or cut, or electrical insulation may break due to repeated flexing at the exit point. Rubber, plastic or plastic coated metal grommets are used to avoid this; the grommet could protect the wiring/cabling from contamination from dirt, water, etc. The smooth and sometimes soft inner surface of the grommet shields the wire from damage. Grommets are used whenever wires pass through punched/drilled sheet metal or plastic casings for this reason. Molded and continuous strip grommets known as edge grommets, are manufactured in a wide variety of sizes and lengths expressly for this purpose. Two-piece hard plastic devices are available which grip the wire that passes through; these are called strain relief bushings and are used to insulate and protect power cords where they enter panels.
Preventing a tug or twist on the wire from stressing the electrical connections inside the connected equipment. Sleeved grommets have a flexible extension tapered or moulded to flex towards the free end in order to reduce fracturing of electrical insulation. Grommets made of rubber or other elastic material are used to minimize the transmission of vibration, they were used for mounting shock-sensitive computer disk drives in equipment subject to vibration or jarring, but are not used with more robust modern drives. The screws that hold the drive in place pass through grommets that decouple it acoustically from the chassis. Grommets are used in a similar way to acoustically isolate electronic circuit components that are susceptible to microphonism caused by mechanical vibration or jarring. In chronic cases of otitis media with effusions present for months, surgery is sometimes performed to insert a grommet, called a "tympanostomy tube" into the eardrum to allow air to pass through into the middle ear, thus release any pressure buildup and help clear excess fluid within.
This is a correcting measure for a patulous Eustachian tube. Blind rivet Cable grommet Cringle Shoulder washer Media related to Grommets at Wikimedia Commons The dictionary definition of grommet at Wiktionary
A latch or catch is a type of mechanical fastener that joins two objects or surfaces while allowing for their regular separation. A latch engages another piece of hardware on the other mounting surface. Depending upon the type and design of the latch, this engaged bit of hardware may be known as a keeper or strike. A latch is not the same as the locking mechanism of a door or window, although they are found together in the same product. Latches range in complexity from flexible one-piece flat springs of metal or plastic, such as are used to keep blow molded plastic power tool cases closed, to multi-point cammed latches used to keep large doors closed. A single-throw bolt; the bolt can be engaged in its strike plate. The locking mechanism prevents the bolt from being retracted by force. Latchbolt or Latch bolt An common latch type part of a lockset, it is a spring-loaded bolt with an angled edge; when the door is pushed closed, the angled edge of the latchbolt engages with the lip of the strike plate.
Once the door is closed, the bolt automatically extends into the strike plate, holding the door closed. The latchbolt is disengaged when the user turns the door handle, which via the lockset's mechanism, manually retracts the latchbolt, allowing the door to open. Deadlocking latchbolt is an elaboration on the latchbolt which includes a guardbolt to prevent “shimming” or “jimmying” of the latch bolt; when the door is closed, the latchbolt and guardbolt are retracted together, the door closes with the latchbolt entering the strike plate. The strike plate, holds the guardbolt in its depressed position: a mechanism within the lockset holds the latchbolt in the projected position; this arrangement prevents the latchbolt from being depressed through the use of a credit card or some other tool, which would lead to unauthorized entry. Draw Latch is a two part latch where one side has an arm that can clasp to the other half, as it closes the clasp pulls the two parts together. Used on tool boxes, chests and windows.
Doesn't need to be closed to secure both halves. Spring bolt lock: A locking mechanism used with a latchbolt A slam latch uses a spring and is activated by the shutting or slamming of a door. Like all latches, a slam latch; the slam latch derives its name from its ability to slam doors and drawers shut without damaging the latch. A slam latch is rugged and ideal for industrial and construction applications. A cam lock is a type of latch consisting of a cam; the base is where the key or tool is used to rotate the cam, what does the latching. Cams can offset. Found on garage cabinets, file cabinets, tool chests, other locations where privacy and security is needed. A Norfolk latch is a type of latch incorporating a simple thumb-actuated lever and used to hold wooden gates and doors closed. In a Norfolk latch, the handle is fitted to a backplate independently of the thumb piece. Introduced around 1800–1820, Norfolk latches, originating in the English county of the same name, differ from the older Suffolk latch, which lacked a back plate to which the thumbpiece is attached.
A Suffolk latch is a type of latch incorporating a simple thumb-actuated lever and used to hold wooden gates and doors closed. The Suffolk latch originated in the English county of Suffolk in the 16th century and stayed in common use until the 19th century, they have come back into favour on garden gates and sheds. They were common from the 17th century to around 1825, their lack of a back plate made them different from the and neighbouring Norfolk latch. Both the Suffolk latch and Norfolk latch are thought to have been named by architectural draughtsman William Twopenny. Many of these plates found their way into other parts of the world. A crossbar, sometimes called a bolt, is a primitive fastener consisting of a post barring a door. Crossbars were common, simple fasteners consisting of a plank or beam mounted to one side of a door by a set of cleats; the board could be slid past the frame to block the door. Alternatively, the bar can be a separate piece, placed into open cleats or hooks, extending across the frame on both sides.
The effect of this device is the opposite of the crash bar in that its operation is to permit the door to be opened inward rather than outward. On a set of double doors, the same principle needn't extend past the frame; the bar extends into another set of cleats on the other door such as to interfere with the door opening. A cabin hook is a hooked bar; the bar is attached permanently to a ring or staple, fixed with screws or nails to woodwork or a wall at the same level as the eye screw. The eye screw is screwed into the adjacent wall or onto the door itself. Used to hold a cupboard, door or gate open or shut. A cabin hook is used in many situations to hold a door open, like on ships to prevent doors from swinging and banging against other woodwork as the ship moves due to wave action; this usage spread to other domains, where a door was required to be held open or a self-closing device is used to close the door. Many buildings are built with fire-resistant doors to separate different parts of buildings and to allow people to be protected from fire and smoke.
When using a cabin hook in such a situation, one should keep in mind that a fire-resistant door is an expensive and h
A pulley is a wheel on an axle or shaft, designed to support movement and change of direction of a taut cable or belt, or transfer of power between the shaft and cable or belt. In the case of a pulley supported by a frame or shell that does not transfer power to a shaft, but is used to guide the cable or exert a force, the supporting shell is called a block, the pulley may be called a sheave. A pulley may have a groove or grooves between flanges around its circumference to locate the cable or belt; the drive element of a pulley system can be a rope, belt, or chain. Hero of Alexandria identified the pulley as one of six simple machines used to lift weights. Pulleys are assembled to form a block and tackle in order to provide mechanical advantage to apply large forces. Pulleys are assembled as part of belt and chain drives in order to transmit power from one rotating shaft to another. A set of pulleys assembled. Two blocks with a rope attached to one of the blocks and threaded through the two sets of pulleys form a block and tackle.
A block and tackle is assembled so one block is attached to fixed mounting point and the other is attached to the moving load. The ideal mechanical advantage of the block and tackle is equal to the number of parts of the rope that support the moving block. In the diagram on the right the ideal mechanical advantage of each of the block and tackle assemblies shown is as follows: Gun tackle: 2 Luff tackle: 3 Double tackle: 4 Gyn tackle: 5 Threefold purchase: 6 A rope and pulley system—that is, a block and tackle—is characterised by the use of a single continuous rope to transmit a tension force around one or more pulleys to lift or move a load—the rope may be a light line or a strong cable; this system is included in the list of simple machines identified by Renaissance scientists. If the rope and pulley system does not dissipate or store energy its mechanical advantage is the number of parts of the rope that act on the load; this can be shown. Consider the set of pulleys that form the moving block and the parts of the rope that support this block.
If there are p of these parts of the rope supporting the load W a force balance on the moving block shows that the tension in each of the parts of the rope must be W/p. This means. Thus, the block and tackle reduces the input force by the factor p; the simplest theory of operation for a pulley system assumes that the pulleys and lines are weightless, that there is no energy loss due to friction. It is assumed that the lines do not stretch. In equilibrium, the forces on the moving block must sum to zero. In addition the tension in the rope must be the same for each of its parts; this means that the two parts of the rope supporting the moving block must each support half the load. These are different types of pulley systems: Fixed: A fixed pulley has an axle mounted in bearings attached to a supporting structure. A fixed pulley changes the direction of the force on a rope or belt that moves along its circumference. Mechanical advantage is gained by combining a fixed pulley with a movable pulley or another fixed pulley of a different diameter.
Movable: A movable pulley has an axle in a movable block. A single movable pulley is supported by two parts of the same rope and has a mechanical advantage of two. Compound: A combination of fixed and movable pulleys forms a block and tackle. A block and tackle can have several pulleys mounted on the fixed and moving axles, further increasing the mechanical advantage; the mechanical advantage of the gun tackle can be increased by interchanging the fixed and moving blocks so the rope is attached to the moving block and the rope is pulled in the direction of the lifted load. In this case the block and tackle is said to be "rove to advantage." Diagram 3 shows that now three rope parts support the load W which means the tension in the rope is W/3. Thus, the mechanical advantage is three. By adding a pulley to the fixed block of a gun tackle the direction of the pulling force is reversed though the mechanical advantage remains the same, Diagram 3a; this is an example of the Luff tackle. The mechanical advantage of a pulley system can be analyzed using free body diagrams which balance the tension force in the rope with the force of gravity on the load.
In an ideal system, the massless and frictionless pulleys do not dissipate energy and allow for a change of direction of a rope that does not stretch or wear. In this case, a force balance on a free body that includes the load, W, n supporting sections of a rope with tension T, yields: n T − W = 0; the ratio of the load to the input tension force is the mechanical advantage MA of the pulley system, M A = W T = n. Thus, the mechanical advantage of the system is equal to the number of sections of rope supporting the load. A belt and pulley system is characterised by two or more pulleys in common to a belt; this allows for mechanical power and speed to be transmitted across axles. If the pulleys are of differing diameters, a mechanical advantage is realised. A belt drive is analogous to that of a chain drive. In the case of a drum-style pulley, without a groove or flanges, the pulley is convex to keep the flat belt centred, it is sometimes referred to as a
Lumber or timber is a type of wood, processed into beams and planks, a stage in the process of wood production. Lumber is used for structural purposes but has many other uses as well. There are two main types of lumber, it may be surfaced on one or more of its faces. Besides pulpwood, rough lumber is the raw material for furniture-making and other items requiring additional cutting and shaping, it is available in many species hardwoods. Finished lumber is supplied in standard sizes for the construction industry – softwood, from coniferous species, including pine and spruce, hemlock, but some hardwood, for high-grade flooring, it is more made from softwood than hardwoods, 80% of lumber comes from softwood. In the United States milled boards of wood are referred to as lumber. However, in Britain and other Commonwealth nations, the term timber is instead used to describe sawn wood products, like floor boards. In the United States and Canada timber describes standing or felled trees. In Canada, lumber describes cut and surfaced wood.
In the United Kingdom, the word lumber is used in relation to wood and has several other meanings, including unused or unwanted items. Referring to wood, Timber is universally used instead. Remanufactured lumber is the result of secondary or tertiary processing/cutting of milled lumber, it is lumber cut for industrial or wood-packaging use. Lumber is cut by ripsaw or resaw to create dimensions that are not processed by a primary sawmill. Resawing is the splitting of 1-inch through 12-inch hardwood or softwood lumber into two or more thinner pieces of full-length boards. For example, splitting a ten-foot 2×4 into two ten-foot 1×4s is considered resawing. Structural lumber may be produced from recycled plastic and new plastic stock, its introduction has been opposed by the forestry industry. Blending fiberglass in plastic lumber enhances its strength and fire resistance. Plastic fiberglass structural lumber can have a "class 1 flame spread rating of 25 or less, when tested in accordance with ASTM standard E 84," which means it burns slower than all treated wood lumber.
Logs are converted into timber by being hewn, or split. Sawing with a rip saw is the most common method, because sawing allows logs of lower quality, with irregular grain and large knots, to be used and is more economical. There are various types of sawing: Plain sawn – A log sawn through without adjusting the position of the log and the grain runs across the width of the boards. Quarter sawn and rift sawn – These terms have been confused in history but mean lumber sawn so the annual rings are reasonably perpendicular to the sides of the lumber. Boxed heart – The pith remains within the piece with some allowance for exposure. Heart center – the center core of a log. Free of heart center – A side-cut timber without any pith. Free of knots – No knots are present. Dimensional lumber is lumber, cut to standardized width and depth, specified in inches. Carpenters extensively use dimensional lumber in framing wooden buildings. Common sizes include 2×4, 2×6, 4×4; the length of a board is specified separately from the width and depth.
It is thus possible to find 2×4s that are four and twelve feet in length. In Canada and the United States, the standard lengths of lumber are 6, 8, 10, 12, 14, 16, 18, 20, 22 and 24 feet. For wall framing, "stud" or "precut" sizes are available, are used. For an eight-, nine-, or ten-foot ceiling height, studs are available in 92 5⁄8 inches, 104 5⁄8 inches, 116 5⁄8 inches; the term "stud" is used inconsistently to specify length. Under the prescription of the Method of Construction issued by the Southern Song government in the early 12th century, timbers were standardized to eight cross-sectional dimensions. Regardless of the actual dimensions of the timber, the ratio between width and height was maintained at 1:1.5. Units are in Song Dynasty inches. Timber smaller than the 8th class were called "unclassed"; the width of a timber is referred to as one "timber", the dimensions of other structural components were quoted in multiples of "timber". The dimensions of timbers in similar application show a gradual diminution from the Sui Dyansty to the modern era.
The length of a unit of dimensional lumber is limited by the height and girth of the tree it is milled from. In general the maximum length is 24 ft. Engineered wood products, manufactured by binding the strands, fibers, or veneers of wood, together with adhesives, to form composite materials, offer more flexibility and greater structural strength than typical wood building materials. Pre-cut studs save a framer much time, because they are pre-cut by the manufacturer for use in 8-, 9-
Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic material, a natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin that resists compression. Wood is sometimes defined as only the secondary xylem in the stems of trees, or it is defined more broadly to include the same type of tissue elsewhere such as in the roots of trees or shrubs. In a living tree it performs a support function, enabling woody plants to grow large or to stand up by themselves, it conveys water and nutrients between the leaves, other growing tissues, the roots. Wood may refer to other plant materials with comparable properties, to material engineered from wood, or wood chips or fiber. Wood has been used for thousands of years for fuel, as a construction material, for making tools and weapons and paper. More it emerged as a feedstock for the production of purified cellulose and its derivatives, such as cellophane and cellulose acetate.
As of 2005, the growing stock of forests worldwide was about 434 billion cubic meters, 47% of, commercial. As an abundant, carbon-neutral renewable resource, woody materials have been of intense interest as a source of renewable energy. In 1991 3.5 billion cubic meters of wood were harvested. Dominant uses were for building construction. A 2011 discovery in the Canadian province of New Brunswick yielded the earliest known plants to have grown wood 395 to 400 million years ago. Wood can be dated by carbon dating and in some species by dendrochronology to determine when a wooden object was created. People have used wood for thousands of years for many purposes, including as a fuel or as a construction material for making houses, weapons, packaging and paper. Known constructions using wood date back ten thousand years. Buildings like the European Neolithic long house were made of wood. Recent use of wood has been enhanced by the addition of bronze into construction; the year-to-year variation in tree-ring widths and isotopic abundances gives clues to the prevailing climate at the time a tree was cut.
Wood, in the strict sense, is yielded by trees, which increase in diameter by the formation, between the existing wood and the inner bark, of new woody layers which envelop the entire stem, living branches, roots. This process is known as secondary growth; these cells go on to form thickened secondary cell walls, composed of cellulose and lignin. Where the differences between the four seasons are distinct, e.g. New Zealand, growth can occur in a discrete annual or seasonal pattern, leading to growth rings. If the distinctiveness between seasons is annual, these growth rings are referred to as annual rings. Where there is little seasonal difference growth rings are to be indistinct or absent. If the bark of the tree has been removed in a particular area, the rings will be deformed as the plant overgrows the scar. If there are differences within a growth ring the part of a growth ring nearest the center of the tree, formed early in the growing season when growth is rapid, is composed of wider elements.
It is lighter in color than that near the outer portion of the ring, is known as earlywood or springwood. The outer portion formed in the season is known as the latewood or summerwood. However, there are major differences, depending on the kind of wood; as a tree grows, lower branches die, their bases may become overgrown and enclosed by subsequent layers of trunk wood, forming a type of imperfection known as a knot. The dead branch may not be attached to the trunk wood except at its base, can drop out after the tree has been sawn into boards. Knots affect the technical properties of the wood reducing the local strength and increasing the tendency for splitting along the wood grain, but may be exploited for visual effect. In a longitudinally sawn plank, a knot will appear as a circular "solid" piece of wood around which the grain of the rest of the wood "flows". Within a knot, the direction of the wood is up to 90 degrees different from the grain direction of the regular wood. In the tree a knot is either the base of a dormant bud.
A knot is conical in shape with the inner tip at the point in stem diameter at which the plant's vascular cambium was located when the branch formed as a bud. In grading lumber and structural timber, knots are classified according to their form, size and the firmness with which they are held in place; this firmness is affected by, among other factors, the length of time for which the branch was dead while the attaching stem continued to grow. Knots materially affect cracking and warping, ease in working, cleavability of timber, they are defects which weaken timber and lower its value for structural purposes where strength is an important consideration. The weakening effect is much more serious when timber is subjected to forces perpendicular to the grain and/or tension than when under load along the grain and/or compression; the extent to which knots affect the strength of a beam depends upon their position, size and condition. A knot on the upper side is compressed. If there is a season check
In woodworking and construction, a nail is a small object made of metal, used as a fastener, as a peg to hang something, or sometimes as a decoration. Nails have a sharp point on one end and a flattened head on the other, but headless nails are available. Nails are made in a great variety of forms for specialized purposes; the most common is a wire nail. Other types of nails include pins, brads and cleats. Nails are driven into the workpiece by a hammer, a pneumatic nail gun, or a small explosive charge or primer. A nail holds materials together by friction in the axial shear strength laterally; the point of the nail is sometimes bent over or clinched after driving to prevent pulling out. The history of the nail is divided into three distinct periods: Hand-wrought nail Cut nail Wire nail The first nails were made of wrought-iron. Nails date back at least to Ancient Egypt — bronze nails found in Egypt have been dated 3400 BC; the Bible provides a number of references to nails, including the story in Judges of Jael the wife of Heber, who drives a nail into the temple of a sleeping Canaanite commander.
The Romans made extensive use of nails. The Roman army, for example, left behind seven tons of nails when it evacuated the fortress of Inchtuthil in Perthshire in the United Kingdom in 86 to 87 CE; the term "penny", as it refers to nails originated in medieval England to describe the price of a hundred nails. Nails themselves were sufficiently valuable and standardized to be used as an informal medium of exchange; until around 1800 artisans known as nailers or nailors made nails by hand – note the surname Naylor. At the time of the American Revolution, England was the largest manufacturer of nails in the world. Nails were expensive and difficult to obtain in the American colonies, so that abandoned houses were sometimes deliberately burned down to allow recovery of used nails from the ashes; this became such a problem in Virginia that a law was created to stop people from burning their houses when they moved. Families had small nail-manufacturing setups in their homes. Thomas Jefferson wrote in a letter: "In our private pursuits it is a great advantage that every honest employment is deemed honorable.
I am myself a nail maker." The growth of the trade in the American colonies was theoretically held back by the prohibition of new slitting mills in America by the Iron Act of 1750, though there is no evidence that the Act was enforced. The production of wrought-iron nails continued well into the 19th century, but was reduced to nails for purposes for which the softer cut nails were unsuitable, including horseshoe nails; the slitting mill, introduced to England in 1590, simplified the production of nail rods, but the real first efforts to mechanise the nail-making process itself occurred between 1790 and 1820 in the United States and England, when various machines were invented to automate and speed up the process of making nails from bars of wrought iron. These nails were known as cut nails or square nails because of their rectangular cross section. Cut nails were one of the important factors in the increase in balloon framing beginning in the 1830s and thus the decline of timber framing with wooden joints.
Though still used for historical renovations, for heavy-duty applications, such as attaching boards to masonry walls, cut nails are much less common today than wire nails. The cut-nail process was patented in America by Jacob Perkins in 1795 and in England by Joseph Dyer, who set up machinery in Birmingham; the process was designed to cut nails from sheets of iron, while making sure that the fibres of the iron ran down the nails. The Birmingham industry expanded in the following decades, reached its greatest extent in the 1860s, after which it declined due to competition from wire nails, but continued until the outbreak of World War I; as the name implies, wire nails are formed from wire. Coils of wire are drawn through a series of dies to reach a specific diameter cut into short rods that are formed into nails; the nail tip is cut by a blade. Other dies are used to cut ridges. Wire nails were known as "French nails" for their country of origin. Belgian wire nails began to compete in England in 1863.
Joseph Henry Nettlefold was making wire nails at Smethwick by 1875. Over the following decades, the nail-making process was completely automated; the industry had machines capable of producing huge numbers of inexpensive nails with little or no human intervention. With the introduction of cheap wire nails, the use of wrought iron for nail making declined, as more did the production of cut nails. In the United States, in 1892 more steel-wire nails were produced than cut nails. In 1913, 90% of manufactured nails were wire nails. Nails went from being precious to being a cheap mass-produced commodity. Today all nails are manufactured from wire, but the term "wire nail" has come to refer to smaller nails available in a wider, more